In Chapter 5, in the discussion of Church modes, it was noted that
the Dorian, Phrygian, Lydian, Mixolydian, and Locrian modes have
certain properties that cause problems when it comes to creating
chord progressions.

Now
that you’ve slogged your way through this long, excruciating chapter on harmonic
scales and you know all about Chase charts and how they work, you might be
wondering whether or not you could construct viable harmonic scales using the
Church modes.

Time to find out.

First, a brief summary of the rules governing the construction of
a harmonic scale:

1.A
“default” harmonic scale consists of seven chords, each rooted on one of the
seven different notes of the diatonic scale.

2.Each
“default” chord is a simple triad. For example, in the key of C major/A minor:

•There are three major triads, C, F, and G

•There are three minor triads, Am, Dm, and Em

•There
is one diminished triad, Bº

3.The chords are arranged in a circle with chord roots five
semitones apart (fifth progressions down, going clockwise).
The only exception is the six-semitone interval between the
triad rooted on the note F and the triad rooted on the note B.

4.The dominant chords with respect to the tonic major and tonic
relative minor chords both get converted to V7 chords to
provide the dynamic directionality required to establish tonal
centres.

Figure 122 below shows the default circular harmonic scale for the
key of C / Am (the Ionian and Aeolian modes, respectively). Inside
the circle are the Nashville Numbers and also the number of
semitones between chord roots. For example, the number of
semitones between the C major chord root and the F major chord
root is five.

The three chords of the major mode and the three chords of the
minor mode each form a grouping of three consecutive chords. The
major and minor modes sound entirely different, which makes for
striking natural harmonic contrast within a cohesive harmonic
framework. The oddball six-semitone interval, and the rootless,
dissonant diminished chord, are located, conveniently, between the
chord groupings of the two modes.

To hear what a Dorian mode scale sounds like, play the white keys
on the piano beginning and ending with D:

D – E – F – G – A – B
– C – D

(Remember,
you can play a Dorian mode scale beginning with any note—it doesn’t have to be
D—so long as you preserve the
order of tones and semitones for the mode. This applies to all the
modes.)

The
Dorian mode is considered to be a minor mode because the third note of the scale
forms a minor third interval with the tonic note (in the above example, D – F).
So the “tonic chord” of the Dorian mode is a minor chord, Dm, in this example
(the notes D, F and A).

As shown in the example below (Figure 123), there are two
possible relative keys: one with the note B as the tonic, the other
with the note F as the tonic. No others are possible because their
chords would overlap with one or more of the chords of the modal
key.

When you apply the above-listed harmonic scale rules to the
Dorian mode, you get two possible versions. One version has the VI
chord (B in the example below) as the tonic of the relative key, the
other has the III chord (F in the example) as the relative tonic.

FIGURE 123 Chase Charts of Dorian Mode
Harmonic Scales

Here are the main problems with Dorian harmonic scales:

•The tonic chord of the Dorian scale is minor (Dm in the
example), which clashes with the subdominant (G, a major
chord).

•The
dominant chord, A7, has a non-modal note, C♯, which removes the “Dorian” sound
of the mode. But if you replace C♯ with C or D, you lose the tritone. You also
lose the leading tone and the power to establish tonality.

The Phrygian scale corresponds to the white keys beginning and
ending with E:

E – F – G – A – B – C
– D – E

Like
the Dorian mode, the Phrygian is considered a minor mode. The third note of the
scale forms a minor third with the tonic (in this example E – G), making the
tonic chord a minor triad (Em).

And, like the Dorian, there are two possible relative keys, one
with VI as the tonic, the other with III as the tonic.

When you apply the harmonic scale construction rules to the
Phrygian mode, you get the two possible versions shown in the
example below (Figure 124).

FIGURE 124 Chase Charts of Phrygian Mode
Harmonic Scales

This time, things look somewhat more promising than the Dorian
harmonic scales.

•The
three principal chords in the above example, Em, Am, and B7, are identical to
the chords of the key of E minor. So at least it’s possible to establish
tonality around the I chord.

•If
you consider C as the relative key, its three principal chords are identical to
the chords of the key of C major.

•If
you consider G as the relative key, its three principal chords are identical to
the chords of the key of G major.

But
the Phrygian mode has an Achilles heel. As with the Dorian mode, it’s the
dominant seventh chord—B7 in the above example.

Recall that the dominant seventh chord is the only chord in
harmony that has these two properties:

•Directionality:
it “points” to the tonal centre.

•Unrest:
it “demands” resolution, specifically to the tonic chord.

The
dominant seventh is therefore crucial in establishing tonality. That’s why it’s
called the dominant chord. It serves as the gateway, the means of gaining
access to a defined tonal centre. Without the dominant chord, no tonal centre
exists. There’s no cadence effect and your brain senses no meaningful harmonic
cohesion.

The
main problem with the Phrygian mode is that the dominant seventh chord, B7,
contains two non-modal notes, D♯ and F♯. So, using B7 as the dominant chord does
not establish tonality in the Phrygian mode. It establishes tonality in the key of E minor. To
create Phrygian tonality, you would need to do something about
those two non-modal notes in the B7 chord to fix things up.

But
you can’t:

•In
the above example, if you change the D♯ to D or E, you lose the leading tone and
the tritone.

•If,
instead, you raise the F♯ to G, you get the chord B7♯5 (B seventh, augmented
fifth), which removes the tritone and the resolution potential to the third note
of the tonic scale. (And, of course, the D♯ note remains a problem.)

•If,
instead, you lower the F♯ to F, you get the chord B7♭5, which removes the
perfect fifth interval and introduces a second tritone (B – F, in addition to
the B7 chord’s normal tritone, D♯ – A). The battling tritones negate the
directionality of the chord.

•If
you try to change both of the non-modal notes, you get similar undesired
effects. For example, if you lower both D♯ and F♯, you get the chord Bm7♭5. Mere
anarchy is loosed upon the world. (Try it!) Indeed, the blood-dimmed tide is
loosed, and W. B. Yeats rises from his grave, looks around, and spots Johann
David Heinichen, also arisen from his grave, autographing copies of the
Circle of Fifths.

Moving on to the Lydian mode, corresponding to the white keys
beginning and ending with F:

F – G – A – B – C –
D – E – F

The
Lydian is considered a major mode. The third note of the scale forms a major
third with the tonic, F – A, in the above example, with the tonic chord being F
major (Figure 125).

FIGURE 125 Chase Chart ofLydian Mode Harmonic
Scale

Of the three principle chords of the Lydian mode, two are
markedly unbalanced, one of which is the rootless diminished IV
chord.

In
the above example, the C7 chord (the V7 chord) contains a non-modal note, B♭, so
establishing true Lydian-sounding tonality is a problem.

•If
you try to fix it by moving B♭ down to A, you get the chord C6 (C sixth). This removes the unrest of the tritone and a good part of the directionality because,
in progressing to the tonic chord, the effect of the semitone resolution from
the note B♭ to the note A vanishes.

•If
you try to fix it by moving B♭ up to B, you get the chord CM7 (C major seventh),
which has no tritone. And you lose the resolution of B♭ to the note A, the tonic
chord’s crucial third-scale-degree note.

As
for possible relative keys, if the VI chord (Dm in the above example) serves as
the tonic, it clashes with the IV chord, G, which is major. If the III chord,
Am, serves as the tonic, the three principal chords are identical to the three
principal chords of the key of A minor, which means the dominant seventh chord
becomes E7— which contains a non-modal note.

Next up: another major mode, the Mixolydian, corresponding to the
white keys on the piano beginning and ending with G:

G – A – B – C – D –
E – F – G

The
chords of the Mixolydian harmonic scale are identical to the normal
(Ionian/Aeolian) harmonic scale except for the transition VII chord at the
bottom, which, in this example, is F major instead of F♯º (Figure 126).

FIGURE 126 Chase Chart ofMixolydian Mode
Harmonic Scale

Once
again, the V7 chord, D7 in the above example, contains a non-modal note, F♯,
making the harmony indistinguishable from the key of G major. If you try to fix
the problem by lowering the F♯ to F, or raising it to G, you lose both the
leading tone and the tritone. Goodbye tonality.

Finally, the Locrian mode, the mode you get when you play the white
keys beginning and ending with B:

B – C – D – E – F – G
– A – B

Harmonically, the Locrian mode begins in the ditch, clutching a
bottle of absinthe, and never manages to crawl out. (Doc Yada-Yadams seems stone cold sober by comparison.)

The tonic of the Locrian is the diminished chord (Figure 127).

FIGURE 127 Chase Chart ofLocrian Mode Harmonic Scale

With
the diminished chord as the tonic, the Locrian mode can’t even think of
establishing tonality.

* * * * *

To
summarize, in all five of the Church modes, you can’t establish mode-defining
tonality using harmonic scale chord progressions due to problems with the V7 – I
progression and numerous other unfortunate harmonic incongruities.

Nevertheless,
these modes—all of them—can serve as excellent source scales for creating
beautiful tunes. The secret is to combine modal tunes with standard major-minor (Ionian-Aeolian) chord
progressions. Chapter 9 discusses how to do this.